Expansion joint



' material remains.

Patented Dec. 6, 1932 UNITED STATES PATENT OFFICE JAMES A. MACDONALD, 0]? LOS ANGELES, CALIFORNIA, ASSIGNOR TO WILLARD WARNE, 01 LOS ANGELES, CALIFORNIA, OPERATING UNDER THE FICTITIOUS NAME OF WILLARD WARNE COMPANY EXPANSION JOINT No Drawing.

Heretofore, it has been the custom to manufacture expansion joints for pavements by saturating a body of fibers, felts, inert fillers, fabrics and the like with an asphaltic binder or bituminous material. These joints are formed in blocks. It is a well known fact that joints made up of a preponderance of bituminous material have no resiliency. When such joints are subjected to compression, they will deform, and due to their lack of elasticity, will not return to their original shape. The binder being viscous and preponderant in the composition compression of the preformed joint will cause exudation of the binder. Due to the mastic'qualities, the joint material wheninstallcd between pavement .slabs is squeezed up on. expansion of the slabs and remains extruding until vehicular trailic flattens and spreads it in an unsightly thickened bump over the pavement joint. Upon contraction of the pavement slabs, the expansion joint does not follow and leaves crevices where foreign material and water may seep through and ruin the subgrade. In many instances the expansion joint block creeps to the pavement surface, being graduallyerodcd and, finally, no expansion joint The result is that the pavement joint is left unfilled. V

'Asphalts and coal tars or their various blends are usually in a solid state when cold, and upon the application of heat change slow-- 1y from a solid to a slow moving viscous semisolid and then to aliquid, depending upon their nature and the amountof heat used. It is therefore obvious that materials composed of the above substances vary in their functioning proportionate to temperature.

It is the primary object of this invention to provide a joint having inherent resiliency, characteristics such that it will follow the pavement joint movements and return to its original shape, is substantially impermeable to moisture, is rigid enough for handling and will not disintegrate under temperature changes, and strains due to compression and expansion. 7

In the present invention or new joint, :1

material that functions equally well in either extremes of warm or cold weather is used.

Application filed May 5, 1931. Serial No. 535,305.

Substantially, the joint is composed as follows: Graded cork granules are assembled and placed in a forming press. Heat and pressure are then both added until the natural resin present in the cork is exuded and forms a thin film around each ranule binding the granules together in a hrm, compact and waterproof slab. These consolidated slabs are resilient'and elastic to a high degree and are not affected by changes in temperature. A covering of either waterproofed fabric or paper is then applied to the outside of these slabs for rigidity and ease in handling. The cover sheet may be impregnated with asphalt and adheres tothe cork body. These slabs, when out to proper shape for use in roadway sections or otherwise are firm,

rigid, light in weight and will compress to within onequarter of their original thickness without any appreciable distortion or elongation. When the compression is released the material will assume its former thickness and repeat this function as long as required by the paving section. This joint material is radically different from those composed of various bituminous fillers and compounds, and functions independent of adhesion to paving, weather conditions, and" 

